1. Field of the Invention
The invention relates to control systems, and more particularly, to a method for operating a control computer. The invention also relates to an arrangement configured to implement the method.
2. Description of the Related Art
Siemens catalogue ST PC, edition November 2008, chapters 2 and 3, discloses industrial PCs, such as control computers, which are provided to solve different automation problems. An industrial PC of this type is usually connected to a system to be controlled, where the industrial PC and the system is connected to a suitable power supply by a line. The industrial PC is switched off in a software-controlled manner which is known per se, by at least one instruction initially being selected and activated by mouse entry or by execution of a control command, as a result of which the industrial PC shuts down automatically. During shut-down, the operating system of the industrial PC terminates running programs, stores data or user settings to be stored on the hard disc or deactivates device drivers. After a shut-down of this type, the industrial PC remains in an idle state or, depending on specifications and settings of a user, the operating system of the industrial PC, in cooperation with corresponding hardware means, automatically switches off the power supply of the industrial PC.
The situation may now arise in which a user not only switches off the system, but instead, as a result of carelessness, switches off the system together with the industrial PC by separating both the system and the industrial PC from the power supply line by a switch. Here, the industrial PC is switched off manually and can no longer shut down correctly. As a result, data can be lost, or a new installation of the operating system of the PC or of a user program may be necessary when the PC is switched on again. To prevent this, the PC can be provided with an “uninterruptible power supply” (UPS), which maintains power to the PC for the duration of the shut-down after the supply voltage has been switched off. An “uninterruptible power supply” of this type requires regular maintenance, within the scope of which accumulators usually have to be replaced.